The present invention relates to a container which is suited for deep freezing suspensions of living cell material in elastic bags.
Deep freezing makes it possible to maintain living biological cells for practically unlimited time. Thus, for example, before interventions which cause great blood loss and which can be scheduled electively, blood is taken from the patient, processed, and subsequently frozen and stored. It is consequently possible to build up a sufficient deposit of the patient's own blood, so that the patient can be provided with his own blood during the operation and afterwards. An infection of the patient with viruses causing hepatitis and HIV, possibly contained in foreign donor blood and not detectable owing to the "diagnostic window," is thereby reliably prevented. Moreover, the deep freezing, generally referred to as cryopreservation, makes possible the preparation of "quarantine preparations" from foreign donor blood, the bridging of temporary bottle-necks, and the stocking of rare blood groups.
Usually, the whole blood preserves which are taken are separated by centrifugation into erythrocytes and blood plasma and are then transferred to bags not affected by low temperatures. These are subsequently deposited in metal containers, with which they are dipped into liquid nitrogen for cooling. In order that the living cells are not damaged or destroyed during freezing, a controlled and rapid cooling with a high rate of cooling is necessary with erythrocytes. The usual metal containers nevertheless have the disadvantage that they enable only a limited heat transfer to the cooling medium so that, with unavoidable geometric inhomogeneities of the bag contained in the container, uncontrolled cooling can occur at least in these partial areas.